4.8 pistons in a 5.3????

[1BAD81BU]

Hey guys I recently aquired what I thought was a 5.3 but now I have some questions about that. I hear that the 4.8 LS engines have flat tops and the 5.3's have dished pistons. Is this true?? If so, what do I have on my hands?? Here's a pic-

Also, I hear that combining the 4.8 pistons with the 5.3 crank and rods will bump up the compression of an LM7 to 10:5.1. Is this also true?? I appreciate the help!! Later on, Nick.

 

[t5montecarlo]

If the 5.3 has dished pistons, it looks like you have a 5.3.

 

[StreetBu]

Correct me if I'm wrong, But I thought all LSX engines had their size cast into the block by the heads where the trans bolts on. What does your say?

 

[v8power]

the blocks say both 5.8 and 5.3 on the sides.

here is the 5.3 i have at the shop. hope this helps

 

[StreetBu]

Now I remember, there is a paint dot next to the size that is. Looks like yours was painted over.

 

[1BAD81BU]

Next question, who makes a forged piston for the 5.3?? I've been told that Mahle does but when I searched their website I had no luck finding anything. I talked to JE over the weekend and they said the cheapest they can cut a set for the 5.3 is $800. I'd like to re-use the 862 heads but I want to bump up the compression around 10:5.1 without milling the heads. Any ideas??

 

[blubaldmontess]

http://cgi.ebay.com/ebaymotors/TSP-LS1-LS2-Forged-Stroker-Rotating-Assembly-402-408_W0QQitemZ300209610602QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item45e5e31f6a&_trksid=p4506.m20.l1116

They have forged kits all over ebay, Eagle makes a lot fo them. Bumping up compression, I'd say the domed pistons like they have on teh lq9 vs the lq4? Heads, find the 314 (or is it 312) aluminum ones that are on the 6.0l as well, or go all out and get the cathedrals off the 6.2L and the intake...they'll make you some power

Good luck!

 

[1BAD81BU]

Just an update for those of you wanting to build an LM7, LM4 or L33. Wiseco DOES make a piston for these engines. They make one for a 3.622 stroke(factory) engine and a 4.000 stroke engine. The bore sizes include a standard size piston and a .20 over piston. Here's a link-http://www.wiseco.com/Catalogs/Automotive/Chevrolet.pdf
Go to page 17 for the details!!! Later on, Nick.

 

[BMR Sales]

Now I remember, there is a paint dot next to the size that is. Looks like yours was painted over.

You cant always trust the paint dot, mine had the dot next to the 5.3 but when I got the casting numbers off the crank and measured the stroke it was a 4.8. The crank casting is what will 100% tell you what you have.